Air conditioning system



Nov. i9, 1940.

L. A. PHILHPP AIR CONDITIONING SYSTEM Filed Feb. l5, 1934 3 Sheets-Sheet l ATTORNEY. l

Nov. 19, 1940. L. A. PHILIPP' AIR CONDITIONING SYSTEM Filed Feb. 15, 1.934

3 Sheets-Sheerl 2 [ig-El:-

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L. A. PHILIPP AIR CONDITIONING SYSTEM Filed Feb. 15, 1934 INVENTOR.

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ATTORNEY.

Patented Nov. 19, 1940 PATENT OFFICE 2,222,242 AIR ooNDrrroNrNe srs'rmu Lawrence A.. Philipp, Detroit, Mich., assigner, by

mesne assignments, to Nash-Kelvinator @orporation, Maryland Detroit, Mich.,

a corporation of Application February rs, ieee, senat Na. 'maar 9 @Elanna -The present invention relates to refrigerating systems and air conditioning systems.

One of the objects of the present invention is to provide an improved method of and apparatus for refrigeration, utilizing an evaporator for cooling and valve mechanism which is adapted to maintain vaporizable refrigerant throughout a large portion of the evaporator at times and at other times limits the flow of refrigerant to the evaporator so that a lesser portion only of the evaporator contains vaporizable refrigerant. in carrying out this object, it is a further object of the invention to control the valve mechanism -in accordance with the relative humidity vof the air to be conditioned.

Further objects and advantages of the present invention will be apparent from the :following description reference being had to the accompanying drawings wherein preferred forms of the embodiment are clearly shown,

In the drawings:

Fig. l is a diagrammatic view of my improved refrigerating apparatus employed in an air conditioning system; I

Fig. 2 is a longitudinal sectional view oi7 an expansion valve used in the apparatus;

Fig. 3 is a sectional view of a shut od valve employed in the apparatus.

Fig. 4 is a diagrammatic view similar toFig. l but showing a different form of expansion mechanism.

Fig. 5 is' a sectional view of one of the valves used inthe system shownI in Fig. 4;

Fig. 6 is a diagrammatic view similar to Fig. l

but showing another form of expansion mechanism and y Fig. 7 is 'a sectional view of the` expansion mechanism employed in Fig. 6.

My invention is particularlyapplicable to air conditioning and includes an evaporator of any suitable type over which air to be conditioned is circulated. Part of the air to be conditioned is circulated over one portion or section of the evaporator for the purpose of removing principally sensible heat from the air and part of the air to be conditioned is circulated over another portion or section of the evaporator,y which latter portion is utilized at times to remove principally latent heat from the air and is utilized, particularly when the air to be conditioned is high in relative humidity, for 'cooling the air to considerably below its dew point in order to cause precipitation and -thereby removal oi? a large part of the moisture from the air.

In the present embodiment the evaporator t@ oi a mechanical refrigerator is formed into two portions or sections 2i and 22. Gaseous refrigerant is withdrawn from the evaporator through a pipe 23 which is connected to the low pressure side oi a compressor 25. When the compressor operates, it withdraws gaseous refrigerant from the evaporator 2t, compresses the refrigerant and forces the saine into a heat dissipator or condenser '2t wherein it is cooled and then lows to a receiver 2l. From the receiver 2l the liquid refrigerant is conducted by a pipe 23 to expansion mechanism generally designated as 3U). ln the illustration shown in Fig. l, the expansion mechanism includes two expansion valves 3i and 32 and a shut off valve tt. Liquid refrigerant from the pipe 28 is fed to expansion valves i511 and 32 by branch pipes 35 and at respectively. From the expansion valve Si the refrigerant is led to the evaporator section 2i by a branch pipe 38 and pipe 39 to the lower header of section 2i. From the expansion valve 32, the refrigerant is conducted also to the lower header of section 2l through a pipe di, valve 34, a branch pipe 42 and pipe 39. rTeus it will be seen that pipe 35, valve 3i and branch pipe 3S parallel branch pipe 36, valve 32, pipe 4i, valve 3d and pipe d2. Refrigerant conducted to the lower header of section 2l ows upwardly through the parallel tubes of the section to the upper header and from the upper header of section 2i by a pipe 43 to the lower header of section 2t. The refrigerant then flows upwardly through the parallel tubes of section 22 to the upper header whence it is conducted to pipe 23.

" Fins 44 are intimately attached to the parallel tubes of the sections to increase the heat absorbing surfaces of the evaporator.

The evaporator 2t is disposed within a compartment 46 of a cabinet tl. This compartment 46 is formed by the front, back and one side wall of the cabinet 4l and by a partition 49 which depends from the top wall of the cabinet and extends from the front to the rear thereof. Air is circulated through the cabinet 41 by a fan 5i which is driven by a motor 52, the air being drawn into the compartment 46 and forced over the evaporator downwardly and then upwardly on the right side of the partition 49 and out through the top of the cabinet. The air passing over the evaporator 2i] will be cooled and it any condensation takes place on the evaporator 2t, the water will drip to the bottom of the cabinet til and from there drain through the drain pipe 563,.

in the present iiluetration. the {'fememtm@ lili of the air in the room, which room is shown diagrammatically by a side wall 55 and a floor 56, is controlled by varying the heat exchange between the evaporator 20 and the air circulating thereover and in the present embodiment, this heat exchange is controlled by intermittently operating the compressor 25. 'I'he compressor is driven by a motor 58 and the starting and stopping thereof is controlled by a thermostat T disposed in the room. The circuit for the motor includes wire 59, thermostat T, wire 60, motor 58 and wire 6|. When the temperature of the room rises to a predetermined maximum, the thermostat completes the motor circuit to cause the compressor 25 to be driven. This will cause refrigeration by the evaporator 20 and a consequent lowering of the air passing thereover. When the temperature of the air is decreased to a predetermined desired minimum, the thermostat T will open the motor circuit and the compressor will stop. In this manner the desired temperature will be maintained in the room.

In addition to controlling the temperature of the air in the room, it is also desirable to control the relative humidity of the air and to accomplish this there is provided the particular type of expansion mechanism 30 and a humidostat H for controlling the same. The expansion valve mechanism 30, humidostat H and the evaporator cooperate at times to maintain both sections of the evaporator at substantially the same temperature when it is desirable to remove principally sensible heat from the air and coop erate at times to cause the section 2| to decrease in temperature so as to remove latent heat from the air.

The expansion valves 3| and 32 are the usual type well known in the art and are identical in structure and the valve 3| will now be described. It comprises a casing 63 having a dividing wall 64 to form a high pressure chamber 65 which is connected with pipe 35 and a low pressure chamber 66 which is connected to pipe 38. One wall of the chamber 66 comprises a flexible diaphragm 61 to which is attached a valve stem 68 carrying a valve 69 which controls the port 10 in the partition wall 64. The back side of the diaphragm 61 is closed by a casing 12 forming a chamber 13. The back side of the diaphragm 61 carries a plate 14 and a spring 15 abuts this plate. The opposite end of the spring 15 abuts an adjusting nut 16 which is utilized for varying the tension on the back side of the diaphragm. A fluid tight cap 11 closes the end of the casing 12. As the pressure Within evaporator 20 decreases, due to the action of the compressor 25, the pressure within chamber 66 is correspondingly decreased so as to open and close the valve 69. Thus the flow of refrigerant to the evaporator 20 through the valve 3| is controlled by the degree of tension of the spring When the valve 34 is closed, all of the refrigerant flows through the expansion valve 3| to the evaporator 20 and the tension of spring 15 is such that a relatively low pressure be maintained in order to pass refrigerant therethrough. The size of thecompressor is such that under this condition vaporizable refrigerant will extend through only the first portion of the evaporator 20 and preferably throughout section 2| thereof and therefore substantially only gaseous refrigerant will be present in section 22. The adjustment of the valve 3| is such that the temperature of section 2| atthis time will be considerably below the dew point of the air passing thereover, whercby the moisture from the air will condense thereon and drip to the bottom of the cabinet 41 and will be drained through the drain pipe 54.

The tension of spring 15 of expansion valve 32 is set, relative to the tension of the like spring in valve 3|, so that the valve 32 will maintain a higher pressure within the evaporator when valve 32 is in control. When it is desirable to remove only or principally sensible heat from the air, the'valve 34 is open and the refrigerating apparatus will then function under the control or valve 32. In this event vaporizable refrigerant will be maintained throughout the greater portion of the evaporator 20, substantially through section 22, at a higher pressure and consequent higher temperature in section 2|. Thus under this condition sections 2| and the major portion of section 22 will be maintained at substantially the same temperature. The port 10 in the expansion valve 32 supplies sufficient refrigerant to the evaporator 20 so that, when valve 34 1s open, the pressure within the evaporator 20 will not be decreased to such low degree as to cause the opening of the expansion valve 3|.

The valve 34 comprises a casing 80 which carries a magnetic coil 89, which when energized raises a solenoid valve 90. When the solenoid valve 90 is raised from its seat 9|, refrigerant can pass from the pipe 4| through the port 92 and chamber 93 of casing 88 4to the pipe 42. Magnetic coil 89 is controlled by a humidostat H and the circuit therefore includes wire 59, thermostat T, wire 95, humidostat H, wire 96, magnetic coil 89 of valve 34, and wires 91 and 6|. When the percentage of relative humidity of the air in the room is above a predetermined desired maximum, the humidostat H in the room, is in a position in which the flow of current to the valve 34 is interrupted whereby valve 34 will be closed and the expansion valve 32 ineffective.' At this time, the flow of refrigerant to the evaporator 20 is controlled solely by the expansion valve 3|. As previously explained, under this condition, the section 2| will be decreased in temperature suifl cient to remove a large portion of moisture from the air circulating thereover. The system will continue to operate in this manner until the relative humidity of the air in the room is lowered to the desired minimum, at which time, the humidostat H will operate to energize coil 89 of valve 34 and thereby render valve 32 effective. Under this latter condition, only or principally sensible heat will be removed from the air flowing over the evaporator 20.

In Figs. 4 and 6, other types of expansion mechanism are shown. In Fig. 4 the expansion valve 3| is adjusted substantially the same as expansion valve 3| of Fig. 1; namely, that it maintains the section 2| of evaporator 20 at a considerably lower temperature than section 22. In the embodiment shown in Fig. 4, there is provided a by-pass for expansion valve 3|,which bypass includes pipe 99, valve 34 and pipe |00. When it is desirable to remove only or principally sensible heat from the air, the valve 34 is opened by the humidostat, as explained with respect to Fig. l and in that event, the flow of refrigerant to the evaporator 20 is controlled by an expansion valve 10|.

In this illustration, the expansion' valve |0| is the high-side-float-type shown in Fig. 5, including a casing |02 having an outlet port |03 which is controlled by a, needle valve |04. The needle valve is carried by a float |05 which is guided by a rod |06 extending into an extension |01. Liquid refrigerant is conducted from the condenser 26 by a pipe |09 to the-chamber ||0 of casing |02 and when a predetermined quantity of liquid refrigerantaccumulates within chamber ||0, the floaty |05 will lift the ,valve |04 ofi. of its seat and permit liquid refrigerant to pass into pipe From the pipe nrefrigerant flows either through the pipe 35 to expansion valve 34 is closed, at which time section 2i will Jim be operating at a relatively low temperatur-diese refrigerant will be contained within the low pressure side of the refrigerating system and cony sequently a larger quantity of refrigerant will be maintained on the high pressure side of the system. In this `latter event sufficient liquid will be maintained in chamber I0 of valve |0| to continuously hold the valve |04 off of its seat Whereby there is a free flow of refrigerant between the condenser 26 and Athe expansion valve 3i and consequently the valve |0| will not function as an expansion Valve and the flow of refrigerant to glie evaporator 20 is controlled entirely by valve In the embodiment illustrated in Fig.. 6 the expansion valve mechanism includes a single expansion valve having a high pressure adjustment and a low pressure adjustment. The refrigerant flows from the receiver 21 through pipe .28, expansion mechanism ||3 and pipe ||4, to the lower header of section 2|. The valve mechanism includes a. casing I5 having a dividing wall IIE to form a high pressure chamber ||1rand a low pressure chamber H8. Pipe 28 is connected with chamber I|1 and pipe ||4 is connected with chamber H0. One wall of chamber ||8 comprises a flexible diaphragm |20l to which is attached a valve stem |2l carrying a valve |22 which controls the flow of refrigerant fromichamber to chamber ||8 through the por-t |23. A reduction` of pressure Within chamber lil, caused `by the operation of the compressor-.25 tends to cause movement of the diaphragm |20 to the left. A spring |25 normally urges the valve |22 towards lts seat and the tension oi this spring must beovercome-before the valve sion of spring |25.

|22 opens the port |23. The tension of this spring can be adjusted by a nut |29. The endof the casing ||5 is closed by a uidtight cap |21.

The back side of the diaphragm |20 is closed by a casing |29 having a fluidtight chamber |29. The casing |28 includes a flexible diaphragm |30 and a spring |3| is interposed between the flexible diaphragm |30 and the flexible diaphragm |20 and normally urges the. diaphragm |20 -to the left and partially counteracts the ten- The back side of diaphragm |30 is closed by a casing |33 having an abutment |34 which is engaged by a disk |35 carried by the diaphragm |30 to limit the right hand movement of diaphragm |30. In this illustration, the ymagneticu coi 99 is contained within casing |33 and operate a solenoid |35. Solenoid |35 actuates a bell crank lever |38 and when energized, tends to rotate the lever |36 in a counterclockwise direction. An arm |31 of the lever i30 engages the disk i35 onediaphragrn |30 when the magnet coil 89 is energized to cause the diaphragm E to move, to the left and thereby increase the tension of`spring i3i. This in effect permits the valve |02 to open the port i23 at a higher pressure. In other words, the valve i122 will open at a higher pressure in the evaporator'v when the magnet coil 89 is energized. The extent or" depression of the spring |3i hy the magnet coil 89 is controlled by the extent of movement of lever i3d and this can be adjusted by the screw i39 which limits the upward movement of the solenoid i35. This screw |39 is threaded in the casing 033 and is adjustably held in position by a loclr nut M0.

When the Irelative humidity of the air in the room is too high, the circuit to the magnetic coil 89 willbe interrupted and a relatively low pressure must be maintained in the evapora-tor 2@ and chamber H8 in order to supply refrigerant to the port G23. This pressure value and consequently the temperature within the evaporator 20 can be regulated by adjusting the tension of spring i25 by the nut 026. At this time the diaphragm |30 will be heid stationary due to the engagement of the disc with the abutment |34. This adjustment may be such, as explained with regard to AFig. l, that substantially only section 2i contains a vaporizable refrigerant and the temperature thereof is considerably below the dew point of the air flowing thereover.

When the relative humidity of the air in the room has been decreased to the desired minimum, fthe humidostat H completes the circuit to magnet coil I9 whereby the arm |31 will force the diaphragm |30 to the left. This will cause an increase in tension of the spring |3| providing a greater force tending to open the valve port |23 which will have the effect of permitting the valve i122 to open its port |23 at a higher pressure. In this manner, a higher pressure will be maintained in the evaporator, and the entire evaporator will then be maintained at substantially the same temperature. The screw |39 can be adjusted so that the pressure in the evaporator is such that the temperature thereof is sufficient to remove only or principally specific heat from the air flowing thereover.

' FromV the foregoing it will .be apparent that I have provided air conditioning systems in which the temperature of the air will be maintained between predetermined high and low temperature limits. The room thermostat T controls the starting and stopping of the compressor 25 to provide the proper temperature of the air and this is accomplished regardless of whether the evaporator sections are functioning to remove both latent and sensible heat or functioning to remove principally sensible heat. It is also apparent that I have provided for maintaining a comfortable humidity condition of the air. The humidostat H controls the expansion mechanism so that the evaporator operates either as a means for removing principally sensible heat or as a means for removing both sensible and latent heat.

Under certain conditions, it will be desirable "to cause some precipitation of moisture at the sections 2| and 22 when these sections are operating at substantially the same temperature,

- and it is to be understood that when said secing at a relatively lower temperature than section Z2.

While the forms of embodiment of the present invention as herein described constitute preferred forms, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

I claim:

1. An air conditioning system comprising in combination, an evaporator, means for withdrawing gaseous refrigerant from the evaporator and for condensing the same and for delivering the condensed1 refrigerant to the evaporator, valve mechanism for controlling the flow of refrigerant to the inlet of the evaporator, said valve mechanism being adapted to maintain vaporizable refrigerant throughout a large portion of the evaporator, means associated with the valve mechanism for limiting the flow of refrigerant to the evaporator so that a lesser portion only of the evaporator contains vaporizable refrigerant, and means cooperating with the associated means and responsive to decreasing and increasing of the relative humidity of the air for respectively increasing and decreasing the extent of vaporizable refrigerant within the evaporator.

2. An air conditioning system comprising in combination, an evaporator, means for withdrawing gaseous refrigerant from the evaporator and for condensing the same and for delivering the condensed refrigerant to the evaporator, valve mechanism at the inlet of the evaporator for controlling the flow of refrigerant to the inlet of the evaporator, said valve mechanism being adapted to maintain at times a certain pressure in the evaporator, means associated with the valve mechanism for maintaining a lower pressure in the evaporator and means responsive to the relative humidity of the air for controlling the associated means.

3. An air conditioning system comprising in combination, an evaporator, means for withdrawing gaseous refrigerant from the evaporator and for condensing the same and for delivering the condensed refrigerant to the evaporator, valve mechanism at the inlet of the evaporator for controlling the flow of refrigerant to the inlet of the evaporator, said valve mechanism being adapted to maintain at times a large portion of the evaporator at substantially the same temperature, means associated with the valve mechanism to maintain at times a smaller portion of the evaporator at a lower temperature, and means responsive to the relative humidity of the air for controlling the associated means.

4. An air conditioning system comprising in combination, an evaporator, means for withdrawing gaseous refrigerant from the evaporator and for condensing the same and for delivering the condensed refrigerant to the evaporator, valve mechanism for controlling the flow of refrigerant to the inlet of the evaporator, said valve mechanism being adapted to maintain a relatively large quantity of vaporizable refrigerant in the evaporator, means associated with the valve mechanism for maintaining a lesser quantity of vaporizable refrigerant in the evaporator, and means cooperating with the associated means and responsive to decreasing and increasing of the relative humidity of the air for respectively increasing and decreasing the quantity of vaporizable refrigerant within the evaporator.

Y5. The method of conditioning air which comprises causing air which is to be conditioned to evaporator.

flow about an evaporator, withdrawing gaseous refrigerant from the evaporator, condensing the refrigerant and delivering the same through expansion mechanism to the inlet of the evaporator, and decreasing and increasing the quantity of vaporizable refrigerant within the evaporator in accordance with increase and decrease respectively of the relative humidity of the air by controlling the flow of refrigerant through the expansion mechanism.

6. The method of conditioning air which comprises causing air which is to be conditioned to flow about an evaporator, withdrawing gaseous refrigerant from the evaporator, condensing the refrigerant and delivering the same through expansion mechanism to the inlet of evaporator, and varying the extent of active refrigerating surface of the evaporator by controlling the flow of refrigerant through the expansion mechanism in accordance with the relative humidity of the air to be conditioned.

7. A refrigerating system for conditioning air comprising in combination, an evaporator, means for withdrawing gaseous refrigerant from the evaporator and for condensing the same and for delivering the condensed refrigerant to the evaporator, an expansion valve for controlling the flow of refrigerant to the evaporator and adapted when effective to maintain a vaporizable refrigerant throughout a large portion of the evaporator, a second expansion valve for controlling the ow of refrigerant to the evaporator and adapted to limit the flow of refrigerant to the evaporator so that a lesser portion only of the evaporator contains vaporizable refrigerant when the first mentioned expansion valve is ineffective, and means operative in response to the relative humidity of the air for rendering the first mentioned expansion valve ineffective.

8. An air conditioning system comprising in combination, an evaporator, means for withdrawing gaseous refrigerant from the evaporator and for condensing the same and for delivering the condensed refrigerant to the evaporator, valve mechanism for controlling the flow of refrigerant to the inlet of the evaporator, said valve mechanism being adapted to maintain vaporizable refrigerant throughout a large portion of the evaporator, and means directly associated with the inlet valve mechanism and responsive to decrease and increase of the relative humidity of the air for causing said valve mechanism to respectively increase and decrease the extent of vaporizable refrigerant within the evaporator.

9. An air conditioning system comprising in combination, an evaporator, means for withdrawing gaseous refrigerant from the evaporator and for condensing the same and for delivering the condensed refrigerant to the evaporator, valve mechanism for controlling the flow of refrigerant to the inlet of the evaporator, said valve mechanism being adapted to maintain vaporizable refrigerant throughout a large portion of the evaporator, means responsive to the temperature of the air for varying the heat exchange between the air and the evaporator, and means directly associated with the inlet valve mechanism and l responsive to decrease and increase of the relative humidity of the air for causing said valve the extent of vaporizable refrigerant within the LAWRENCE A. PHILIPP. 

